[1] Univ Andes, Dept Periodontol, Ctr Biomed Res, Fac Dent, Santiago, Chile
[2] Univ Chile, Dept Pathol, Fac Dent, Santiago, Chile
[3] Univ Mayor, Dept Stat, Fac Dent, Santiago, Chile
[4] Univ Andes, Dept Publ Hlth & Epidemiol, Fac Dent, Santiago, Chile
[5] Hosp Dr Sotero del Rio, Dept Obstet & Gynecol, Ctr Res & Innovat Maternal Fetal Med CIMAF, Santiago, Chile
[6] Pontificia Univ Catolica Chile, Div Obstet & Gynecol, Fac Med, Santiago, Chile
[7] Univ Helsinki, Dept Oral & Maxillofacial Dis, Helsinki, Finland
[8] Helsinki Univ Hosp, Helsinki, Finland
[9] Karolinska Inst, Div Periodontol, Dept Dent Med, Huddinge, Sweden
[10] Univ Andes, Dept Obstet & Gynecol, Ctr Biomed Res, Fac Med, Santiago, Chile